372 REFLEX ACTION, INSTINCT, AND REASON 



wishes. It is true he may set himself sneezing by voluntarily intro- 

 ducing an irritant into his nose ; but the irritant, not the will, is 

 the direct cause of the act. So also he is able to make himself 

 sick by tickling the back of his throat, but he cannot vomit by a 

 pure act of will. Swallowing is another example, and a very good 

 one. The act of swallowing seems at first strictly voluntary. 

 Really it is purely reflex. We are able to swallow only when 

 we have something to swallow ; that is, only when the mechanical 

 stimulus which starts the reflex is present at the back of the throat. 

 The reader can easily test this by swallowing his saliva and then 

 trying to repeat the act. He will succeed only after he has 

 collected more saliva supplied more mechanical stimulus. 



615. The reflexes are all 'inborn and transmissible,' that is 

 they all develop in the individual under the stimulus of nutriment, 

 and reappear in all normal offspring. With rare exceptions, they 

 are extremely useful to him, indeed essential to his survival. For 

 example, no child lives who does not inherit the cardiac and 

 intestinal reflexes which were possessed by his ancestors. The 

 exceptions are one or two reflexes which seem to be mere by- 

 products of evolution traits correlated to more useful traits. The 

 convulsions of tickling are examples. When feeling is associated 

 with the adaptive reflexes it always contributes to their usefulness. 

 In some cases (e.g. the feeling caused by food in the larynx, which 

 in turn causes swallowing) feeling is the discriminating spark which 

 awakens the reflex. In other cases, by promise of pleasure or 

 relief from pain, it awakens desire, which, as in the case of hunger, 

 awakens the will to perform those voluntary actions which 

 necessarily precede and supply the stimulus for the reflex act In 

 some instances, as in the case of the reflexes of the bladder and 

 lower bowel, the will acts usefully, not because, as in the case of 

 swallowing, it initiates the performance of voluntary actions which 

 in turn supply stimuli for reflexes, but because for a longer or 

 shorter time it controls or inhibits the reflexes because it is able 

 to delay their performance till a more convenient time. Such 

 reflexes are always initiated by a feeling which tends to awaken, 

 not only the reflex, but also the will that inhibits it. The duration 

 and amount of the control which the will is capable of exercising 

 is always proportionate to its usefulness. Thus it is short and 

 slight in the case of sneezing as a rule no longer than gives time 

 to swallow food already in the mouth. It is a little longer in the 

 case of breathing. In the case of coughing it is short in proportion 

 to the severity of the irritation. On the other hand the control is 



